1、Designation: A1084 13Standard Test Method forDetecting Detrimental Phases in Lean Duplex Austenitic/Ferritic Stainless Steels1This standard is issued under the fixed designation A1084; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision
2、, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 The purpose of this test method is to allow detection ofthe presence of detrimental chromium-containing
3、phases inselected lean duplex stainless steels to the extent that toughnessor corrosion resistance is affected significantly. Such phasescan form during manufacture and fabrication of lean duplexproducts. This test method does not necessarily detect losses oftoughness nor corrosion resistance attrib
4、utable to other causes,nor will it identify the exact type of detrimental phases thatcaused any loss of toughness or corrosion resistance. The testresult is a simple pass/fail statement.1.2 Lean duplex (austenitic-ferritic) stainless steels are typi-cally duplex stainless steels composed of 30-70 %
5、ferritecontent with a typical alloy composition having Cr 17 % andMo 1 % and with additions of Nickel, Manganese, Nitrogenand controlled low carbon content as well as other alloyingelements. This standard test method applies only to thosealloys listed in Table 1. Similar test methods for some higher
6、alloyed duplex stainless steels are described in ASTM A923,but the procedures described in this standard differ significantlyfor all three methods from the ones described in A923.1.3 Lean duplex stainless steels are susceptible to theformation of detrimental chromium-containing compoundssuch as nitr
7、ides and carbides and other undesirable phases.Typically this occurs during exposures in the temperature rangefrom approximately 300 to 955C (570 to 1750F) with amaximum susceptibility in the temperature range around 650 to750C (1200 to 1385F). The speed of these precipitationreactions is a function
8、 of composition and the thermal orthermo-mechanical history of each individual piece. The pres-ence of an amount of these phases can be detrimental totoughness and corrosion resistance.1.4 Because of the low molybdenum content, lean duplexstainless steels only exhibit a minor susceptibility to sigma
9、 orother types of molybdenum containing intermetallic phases.Heat treatment, that could lead to formation of small amountsof molybdenum containing intermetallics, would result in alarge amount of precipitation of detrimental nitrides or carbides long before any signs of sigma and similar phases woul
10、d beobserved.1.5 Correct heat treatment of lean duplex stainless steels caneliminate or reduce the amount and alter the characteristics ofthese detrimental phases as well as minimizing Cr-depletion inthe matrix phase in the immediate vicinity of these phases.Adequately rapid cooling of the product f
11、rom a suitableannealing temperature provides the maximum resistance toformation of detrimental phases by subsequent thermal expo-sures. For details of the proper annealing temperature recom-mendations for the alloy and product in question, the user isreferred to the relevant applicableASTM product s
12、pecification.1.6 Compliance with the chemical and mechanical require-ments for the applicable product specification does not neces-sarily indicate the absence of detrimental phases in the product.1.7 These test methods include the following:1.7.1 Test Method AEtch Method for detecting the pres-ence
13、of potentially detrimental phases in Lean Duplex StainlessSteels1.7.2 Test Method BCharpy V-notch Impact Test fordetermining the presence of detrimental phases in Lean DuplexStainless Steels.1.7.3 Test Method CInhibited Ferric Chloride CorrosionTest for determining the presence of detrimental phases
14、 in LeanDuplex Stainless Steels.1.7.4 Examples of the correlation of thermal exposures, theoccurrence of detrimental phases, and the degradation oftoughness and corrosion resistance are given in Appendix X2,Appendix X3 and the References.1.8 Guidelines for the required data needed for subcommit-tee
15、A01.14 to consider listing a lean duplex stainless steel inthis standard test method are given in Annex A1.1.9 The values stated in SI units are to be regarded asstandard. The values given in parentheses are mathematicalconversions to other units that are provided for informationonly and are not con
16、sidered standard.1.10 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is the1This test method is under the jurisdiction of ASTM Committee A01 on Steel,Stainless Steel and Related Alloys and is the direct responsibility of SubcommitteeA01.14 on
17、 Methods of Corrosion Testing.Current edition approved June 1, 2013. Published July 2013. DOI: 10.1520/A108413Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1responsibility of the user of this standard to establish appro-priate safety
18、 and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2A370 Test Methods and Definitions for Mechanical Testingof Steel ProductsA923 Test Methods for Detecting Detrimental IntermetallicPhase in Duplex Austenitic/Ferrit
19、ic Stainless SteelsE23 Test Methods for Notched Bar Impact Testing of Me-tallic MaterialsG48 Test Methods for Pitting and Crevice Corrosion Resis-tance of Stainless Steels and Related Alloys by Use ofFerric Chloride Solution3. Terminology3.1 Definitions:3.1.1 The terminology used herein, if not spec
20、ifically de-fined otherwise, shall be in accordance with Terminology G15and Terminology E6. Definitions provided herein and not givenin Terminology G15 or in E6 are limited only to this standard.4. Significance and Use4.1 Test Method A shall only be used to supplement theresults of Test Methods B an
21、d C. It shall not be used as arejection criterion, nor shall it be used as an acceptancecriterion. Test Methods B and C are intended to be theprocedures giving the acceptance criteria for this standard.4.2 Test MethodAcan reveal potentially detrimental phasesin the metallographic structure. As the p
22、recipitated detrimentalphases can be very small, this test demands high proficiencyfrom the metallographer, especially for thinner material.4.3 The presence of detrimental phases is readily detectedby Test Methods B and C provided that a sample of appropriatelocation and orientation is selected.4.4
23、The tests do not determine the precise nature of thedetrimental phase but rather the presence or absence to theextent that the normally expected toughness and corrosionresistance of the material are significantly affected.4.5 This standard covers testing of samples taken from coil,coil- and plate mi
24、ll plate, sheet, tubing, piping, bar anddeformed bar, though some of these products might not besuitable for testing according to Method B (see Test Method Bfor further details). Other product forms have thus far not beensufficiently tested and documented to be an integral part of thisstandard, thou
25、gh the standard does not prohibit testing of theseproduct forms according to the three test methods. For theseother product forms, this standard gives only limited andnon-exhaustive guidance as to interpretation of result andassociated acceptance criteria.4.6 Testing on product forms outside the pre
26、sent scope ofthis standard shall be agreed between purchaser and supplier.5. Sampling, Test Specimens, and Test Units5.1 Sampling:5.1.1 Because the occurrence of detrimental phases is afunction of temperature and cooling rate, it is essential that thetests be applied to the region of the material ex
27、periencing theconditions most likely to promote the formation of detrimentalphases. In the case of common heat treatment, this region canbe that which cooled most slowly or undergoes extremely rapidcooling.5.1.2 For practical purposes, it is considered sufficient thatthe sampling location for flat m
28、ill products be from a locationthat is at least twice the material thickness from the as-heatededges.5.1.3 Purchaser and supplier may agree on more detailedrules regarding the sampling location.5.1.4 The number of samples as well as frequency ofsampling shall be agreed between purchaser and supplier
29、 of thematerial.5.2 Test Specimens and Test Units:5.2.1 Details of test specimen and test unit requirements arelisted together with each of the Test Methods A, B and C.TEST METHOD AETCH METHOD FOREVALUATION OF THE PRESENCE OFPOTENTIALLY DETRIMENTAL PHASES IN LEANDUPLEX STAINLESS STEELS6. Introductio
30、n6.1 The etch test in this standard shall only be used forexploratory purposes. The reason for this is the small size ofthe detrimental phases typically occurring in lean duplexstainless steels and the difficulty in achieving a fully reproduc-ible etch structure, which depends on factors such as spe
31、cimensize and geometry, etching current and potential, compositionof the lean duplex as well as the amount and type ofdetrimental phases present. The test method contained in thisstandard is, however, the best known metallographic procedureto show the appearance and approximate amount of detrimental
32、phases in a lean duplex stainless steel.6.2 As there is no formal test result from the metallographicetch method, the actual test method is attached to this standardas Appendix X1.TEST METHOD BCHARPY V-NOTCH IMPACTTEST FOR DETERMINATION OF THE PRESENCEOF DETRIMENTAL PHASES IN LEAN DUPLEXSTAINLESS ST
33、EELS7. Scope7.1 This test method describes the procedure for conductingthe Charpy V-notch impact test as a method of detecting the2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume informat
34、ion, refer to the standards Document Summary page onthe ASTM website.TABLE 1 List of the Lean Duplex Grades Covered by thisStandardGradesUNS S32101, UNS S32304A1084 132precipitation of detrimental phases in lean duplex stainlesssteels. The presence or absence of an indication of a detrimen-tal phase
35、 in this test is not necessarily a measure of perfor-mance of the material in service with regard to any propertyother than that measured directly. The Charpy V-notch proce-dure as applied here is different from that commonly appliedfor the determination of toughness and shall not be used whencharac
36、terization of material toughness is the purpose of thetesting.8. Significance and Use (Test Method B)8.1 The Charpy V-notch impact test may be used to evaluatemill products, provided that it is possible to obtain a specimenof the proper size from a relevant location.8.2 Charpy V-notch impact toughne
37、ss of a material isaffected by factors other than the presence and absence ofdetrimental phases. These factors are known to include differ-ent compositions, even when the material is in fully annealedcondition; small and otherwise acceptable variations inaustenite/ferrite balance; and the lamellar d
38、istance betweenphases.Testing transverse and longitudinal test specimens frommill products can also give different absolute levels of impacttoughness.8.3 Table 2 indicates the applicability and acceptance crite-ria for Test Method B. These acceptance criteria have beenshown to allow for the natural
39、variation of impact toughness insound material tested in the transverse direction on plate and inthe longitudinal direction on bar and deformed bar, while stillbeing able to identify whether detrimental amounts of unde-sirable phases are present.8.4 Acceptance criteria forTest Method B for other pro
40、ductsincluding mill welded pipe, weldments and weld metal are notpresently covered by this standard, though purchaser andsupplier may agree upon an acceptance criteria (see Note 1).Note that the results of weldment testing will depend on thefiller metal or weld deposit chemistry.8.5 Acceptance crite
41、ria of sub-size specimens are not cov-ered by this standard, though purchaser and supplier may agreeupon a proper conversion factor of the given acceptancecriteria in Table 2. Conversion factors generally vary byproduct type and dimensions of product for which the sub-sizespecimen sampling is needed
42、 (see Note 2).NOTE 1As no data has been presented to A01.14 for welded millproducts or other products, no recommendation can be given as to theacceptance criteria for these products. Any acceptance criteria and otherdetails of the test should be supported with data from a pre-qualificationtest in li
43、ne with the minimum requirements of Annex A1 in this standard.NOTE 2As stated in A370, Appendix A5.3.3 and ASTM E23,Appendix X1.3, there is no general correlation between impact valuesobtained with specimens of different size or shape. However, limitedcorrelations may be established for specificatio
44、n purposes on the basis ofspecial studies of particular materials and particular specimens. It iscommonly seen that the conversion factor is set directly proportional tothe ratio between standard and sub-size specimen fracture surface area ora percentage thereof, though whether this is an acceptable
45、 way forward tostill be able to identify the presence or absence of detrimental phasesneeds to be documented.9. Apparatus9.1 The test apparatus shall be as described in Test Methodsand Definitions A370.10. Test Specimens10.1 General requirements (all products):10.1.1 The test specimen shall be as de
46、scribed in TestMethods and Definitions A370.10.1.2 An impact test for the purpose of detecting detrimen-tal phases shall consist of a single specimen taken from theproduct piece or lot to be represented.10.1.3 Provided purchaser and supplier have agreed upon aproper acceptance criterion, sub-size sp
47、ecimens may be usedfor products with thickness less than that of full-size CharpyV-notch specimen. Required energy for sub-size specimensshall be established and agreed upon based on the specificproduct type and geometry in question.10.2 Flat products (sheet, coil, plate):10.2.1 The specimen shall b
48、e prepared in the transversedirection. The notch shall be perpendicular to the major rolledsurface.10.3 Non-deformed bar products:10.3.1 The specimen shall be prepared in the longitudinaldirection.10.4 Deformed bar products:10.4.1 The specimen shall be prepared in the longitudinaldirection.10.5 Othe
49、r products including mill pipe:10.5.1 When this test is applied to a welded structure or toany product having a less than uniform structure, particularattention shall be paid to the location of the V-notch. Forexample, in the heat-affected zone of a weld, the degree ofdetrimental phase formation can vary significantly over shortdistances as a function of the local thermal cycle. In such cases,the placement of the V-notch can affect the measured resultsignificantly.10.5.2 Following the guidelines of A370, the specimenpreparation method shall be agreed between purchaser and
